Emerging pollutants are compounds of increased environmental importance and, as such there is interest among researchers in the evaluation of their presence, continuity and elimination in different environmental matrices. The present work reviews the available scientific data on the degradation of emerging pollutants, mainly pharmaceuticals, through ultrasound, as an advanced oxidation process (AOP). This study analyzes the influence of several parameters, such as the nature of the pollutant, the ultrasonic frequency, the electrical power, the pH, the constituents of the matrix and the temperature of the solution on the efficiency of this AOP through researches previously reported in the literature. Additionally, it informs on the application of the referred process alone and/or in combination with other AOPs focusing on the treatment of domestic and industrial wastewaters containing emerging pollutants, mainly pharmaceuticals, as well as on the economic costs associated with and the future perspectives that make ultrasound a possible candidate to solve the problem of water pollution by these emerging pollutants..

Biochar is a carbonaceous material, which can be decorated with metals, that has been garnering attention to be used in the treatment of water due to its contribution to waste management and circular economy. This study presents the life cycle assessment (LCA) regarding the generation of Pinus patula raw biochar and its modification with iron (Fe-modified biochar). SimaPro 9.3.0.3 software was used to simulate the environmental impacts of both carbonaceous materials. The potential environmental effects obtained from the production of Pinus patula raw biochar were mainly ascribed to the source of energy utilized during this process. The potential impacts demonstrated that the generation of gases and polycyclic aromatic hydrocarbons are the main concern. In the case of Fe-modified biochar, the potential environmental effects differed only in the stage of the biomass modification with the metal. These effects are associated with the extraction of Fe and the generation of wastewater. These findings provide an insight into the environmental effects linked to the production of raw and Fe-modified biochar. However, further LCA research should be performed concerning other materials and compounds than can be generated during the biomass thermochemical conversion.

In this work, the recent trends in the application of the sulfate radical-based advanced oxidation processes (SR-AOPs) for the treatment of wastewater polluted with emerging contaminants (ECs) and pathogenic load were systematically studied due to the high oxidizing power ascribed to these technologies. Additionally, because of the economic benefits and the synergies presented in terms of efficiency in ECs degradation and pathogen inactivation, the combination of the referred to AOPs and conventional treatments, including biological processes, was covered. Finally, the barriers and limitations related to the implementation of SR-AOPs were described, highlighting the still scarce full-scale implementation and the high operating-costs associated, especially when solar energy cannot be used in the oxidation systems.

When dyes are discharged in water bodies, mutagenic, carcinogenic and teratogenic effects may be caused in both aquatic organisms and human beings. The use of biochar and the implementation of advanced oxidation processes (AOPs) are alternative treatments that have been used individually in the removal of dyes in wastewater. Besides being effective processes acting separately, biochar and AOPs can be coupled, exhibiting synergetic effects in the treatment of dyes contained in water. This work deals with the methods implemented to produce biochar from biomass, its mechanism in the removal of dyes and associated sustainability issues. Additionally, the main AOPs that have been utilized for the removal of dyes from water are covered, as well as the biochar-AOP combined processes. The future prospects for the removal of dyes from water have been also addressed. The coupling of biochar to AOPs has been proven to be more effective in the removal and mineralization of dyes than the individual treatments. In this regard and considering the scarce studies in the field, new horizons are opened on the treatment of water polluted with dyes.